PROJECT SUMMARY/ABSTRACT In addition to their well-known deficits in language learning, young children with autism spectrum disorder (ASD) show abnormal visual preferences for perceptually salient features of the environment (e.g., complex geometric patterns). Recent studies have revealed an association between these two aspects of the ASD phenotype, leading to the provocative hypothesis that abnormal visual preferences have cascading negative effects on language development. However, we do not yet know how abnormal visual preferences impact language in children with ASD, or which children are most vulnerable to these effects. In the absence of such knowledge, we have an incomplete understanding of why these children struggle to learn language and how to alleviate their difficulties. The long-term goal is to identify the developmental mechanisms that underlie language-learning deficits in children with ASD. The overall objective of the proposed project is to determine how abnormal visual preferences impact familiar word processing and novel word learning, and to identify the children who are most severely affected. The central hypothesis is that abnormally strong visual preferences for perceptual salience will disproportionately disrupt word processing and word learning in children with ASD, and that the amount of disruption will correlate with key behavioral characteristics. The rationale is that determining how abnormal visual preferences impact word processing and word learning will help us understand why children with ASD have difficulty learning language, thereby yielding valuable theoretical and clinical advances. Guided by strong preliminary data, the proposed project will investigate three specific aims: 1) To assess the impact of competing perceptual salience on familiar word processing in children with ASD and age-matched, typically developing children; 2) To assess the impact of competing perceptual salience on novel word learning in children with ASD and age-matched, typically developing children; and 3) To identify behavioral characteristics that correlate with the amount of disruption in word processing and word learning created by competing perceptual salience. These aims will be addressed using eye-gaze methodology, an approach that the PI has used extensively and has shown to be feasible with the target populations. Novel adaptations of two well-established eye-gaze tasks will assess the impact of competing perceptual salience on familiar word processing (Aim 1) and novel word learning (Aim 2). Growth curve analyses will measure the amount of disruption experienced by individual children, as well as the contributions of key behavioral characteristics (e.g., receptive vocabulary; Aim 3). The proposed project is innovative because it adopts a novel methodological approach and integrative theoretical framework that maximize its potential to exert a substantial and lasting impact on the field. The proposed research is significant because it is expected to advance theories of autism and language acquisition and enable the development of novel treatment strategies that limit detrimental effects of competing perceptual salience.